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Search: id:A056279
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| A056279 |
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Number of primitive (aperiodic) word structures of length n which contain exactly three different symbols. |
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+0
1
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| 0, 0, 1, 6, 25, 89, 301, 960, 3024, 9305, 28501, 86430, 261625, 788669, 2375075, 7140720, 21457825, 64435896, 193448101, 580597110, 1742343323, 5228050949, 15686335501, 47063113320, 141197991000
(list; graph; listen)
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OFFSET
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1,4
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COMMENT
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Permuting the alphabet will not change a word structure. Thus aabc and bbca have the same structure.
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REFERENCES
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M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia.
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FORMULA
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sum mu(d)*A000392(n/d) where d|n and n>0.
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CROSSREFS
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Cf. A056268.
Sequence in context: A133714 A055585 A099625 this_sequence A055337 A001871 A000392
Adjacent sequences: A056276 A056277 A056278 this_sequence A056280 A056281 A056282
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KEYWORD
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nonn
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AUTHOR
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Marks R. Nester (nesterm(AT)dpi.qld.gov.au)
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